Fatherhood and the Biology of Infant Care Behavior

Early positive parental-infant attachment provides a key developmental advantage.

The maternal-infant dyad has received the most research attention. However, fathers also can play an important role in infant development. An increasing number of studies focus on the biology of fatherhood and infant care behavior.

Ilanit Gordon along with colleagues in Israel and the United States examined the role of two central neuropeptides in paternal behavior during the first six months of infancy.

In their study, 43 fathers with a firstborn infant were studied when the infants were two and six months old. Fathers were rated on levels of emotional synchrony with their infant. Additionally, fathers were rated on levels of paternal involvement in exploratory play.

Paternal serum oxytocin and prolactin levels were obtained at both the two and six month time points. Oxytocin has been identified as a key neuropeptide in maternal-infant bonding, but it's role in fathers is unclear.

The authors found significant relationships between the two hormones and paternal-infant behavior. Paternal serum oxytocin levels correlated with emotional synchrony while serum prolactin levels correlated with coordinated exploratory play.

The authors note in their discussion that prolactin had previously been identified as important in animal studies of fathers but not in humans.

The mechanism of how these two hormones impact paternal behavior is unclear.

A recent study by Mascaro and colleagues suggest neuropeptides may influence specific brain regions known to be important in empathy (anterior insula and inferior frontal gyrus).

In their study, a series of fathers were studied for responsiveness to the cries of children between one and two years of age. Brain regional activation levels were compared across a paternal responsiveness to infant cries.

The key finding in this study was a nonlinear relationship between anterior insula activation and paternal responsiveness. Fathers with a moderate level of activation outperformed fathers with low or high levels of activation. 

These types of studies are important. They may hold promise for improving parental attachment to their children. Additionally, they may provide some insight into the biology of child abuse and neglect. These first studies are limited correlational design studies but they add evidence of the need for additional more complex and sophisticated research.

Readers with more interest in these two studies can get more information by clicking on the PMID links in the citations below.

Image of brain amygdala is a screen shot from the iPad app 3D Brain.

Follow the author on Twitter @WRY999

Gordon I, Zagoory-Sharon O, Leckman JF, & Feldman R (2010). Prolactin, Oxytocin, and the development of paternal behavior across the first six months of fatherhood. Hormones and behavior, 58 (3), 513-8 PMID: 20399783

Mascaro JS, Hackett PD, Gouzoules H, Lori A, & Rilling JK (2014). Behavioral and genetic correlates of the neural response to infant crying among human fathers. Social cognitive and affective neuroscience, 9 (11), 1704-12 PMID: 24336349

Drug Development for Cognitive Enhancement

AMPA (α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate)

Cognitive enhancement seeks to improve cognitive function in healthy adults.  Although medicine typically focuses on treatment of medical disorders, a significant effort is underway to explore the mechanism of human attention, concentration, memory and other cognitive functions.  


Cognitive enhancement does not replace other methods of cognitive performance.  There is no substitute for repetitive practice and learning content through reading, writing, speaking and physical activity.  Cognitive enhancement looks to maximize performance without serious adverse effects risk.  The development of drugs and model molecules related to basic brain is expanding.  


This is really not a new area as man has been using dietary aids to enhance cognition for thousands of years.  Perhaps the best, but not the only, example of this is use of caffeine.  Caffeine can increase performance on a number of tests of cognitive function as well as extend the duration of time for productive activity.


Cognitive enhancement candidate drugs include extension of drug used in attention-deficit hyperactivity disorder (ADHD) as well as drugs designed to reduce the rate of cognitive decline in Alzheimer's disease and other dementias.  This class of pharmacology has been label the nootropic drugs.  de Jongh and colleagues from Utrecht University in the Netherlands recently summarized current and future targets for enhancing cognition.   Here is the listing of drugs from their review:


Currently available enhancers
Donepezil-an anticholinesterase inhibitor indicated for Alzheimer's disease with evidence of improved flight simulator performance after training older pilots
Modafanil-seen as a wakefulness enhancer with FDA approval for those shift work sleep disorder.  Effective at extending helicopter pilot performance effectiveness up to 36 continuous hours.
Dopamine agonists (d-amphetamine, bromocriptine, pergolide)-appears to improve working memory, particularly for those with memory problems or the COMT genotype val/val associated with reduced prefrontal dopamine levels
Guanfacine- Alpha 2 adrenergic receptor agonist approved for ADHD in the U.S. Inconsistent findings of improved memory and executive function 
Methylphenidate--Improves prefrontal cortical function in rodents but ineffective for age related cognitive decline found in older human research volunteers


Future targets
AMPA receptors-Ampakines are drugs that enhance fast excitatory neurotransmission by modulating AMPA (α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate see diagram above)-type glutamate receptors--effective in improving memory and performance after sleep deprivation in monkeys.  Also effective improving memory in healthy elderly (65-75 years of age) human study.
NMDA receptors-D-cycloserine, a partial agonist at the NMDA receptor enhances memory and has been effective in increasing the speed of response to psychotherapy as noted in previous Brain Post commentary here.
CREB (cAMP response element binding protein)-cAMP response element protein a crucial compound in long-term memory formation.  Has problems with adverse effects (anxiety and depression) outside of brain amygdala. 


Mood and pro-social behavior
Antidepressants-may have some ability to increase social behaviors in those without depression, also felt to improve "hassle tolerance"
Oxytocin-increases pro-social behaviors such as pair bonding and maternal care.  Leads to increased trust in others in social game simulations.


Research in this area carriers some significant ethical challenges that will need discussion and consideration.  Nevertheless, look for additional research into "nootropic" drug development.


DEJONGH, R., BOLT, I., SCHERMER, M., & OLIVIER, B. (2008). Botox for the brain: enhancement of cognition, mood and pro-social behavior and blunting of unwanted memories Neuroscience & Biobehavioral Reviews, 32 (4), 760-776 DOI: 10.1016/j.neubiorev.2007.12.001